1. Field of the Invention
The invention relates to a windowpane antenna for use in motor vehicles. More particularly, it relates to a windowpane antenna installation operating in the frequency range for the meter and decimeter wave bands and being used for ultra short-wave and long-wave, medium-wave and short-wave radio reception, as well as terrestrial television reception.
2. The Prior Art
Antennas of this type are described in EP 0 124 055 B1, DE-3410415 A1, as well as De-3618452, among others. With all of the prior art antennas, antenna conductors are printed onto the windowpane, or embedded in laminated glass. In all of these antennas, the antenna conductor connection points are located on the edge of the windowpane and are installed in a conductive windowpane frame represented by the conductive body of the vehicle. According to current technology, the antenna connection points are connected to an electrical unit via feed lines that are made as short as possible. The mass connection of the electrical unit is connected in the shortest possible way to the conductive frame of the rear windowpane.
The electrical unit, which is frequently an antenna amplifier, is connected at its output to the HF-cable, which further transmits the signals to the receiver. Generally, the electrical unit is mechanically fastened near the mass connection on the body of the vehicle. Frequently, the mass connection to the body of the vehicle is established via the installed connection as well.
This method of mounting the electrical unit on the body of the vehicle is both expensive and complex. The method also requires fastening means such as bolts or holes for fastening the unit. It is much more economical and more advantageous for the production of motor vehicles if an electrical unit, designed as a miniaturized unit, is mounted on the edge of a windowpane. Sufficient space is available for the miniaturized unit within the zone of the black printing on the edge of the window. In designing an antenna installation that can be used for high-frequencies, it is generally necessary to connect the high-frequency impedance, which develops between the antenna conductor connection point and an adjacent HF-mass reference point, in a defined way in terms of high frequency to the input of the electrical unit.